SECTION 26 05 73 OVERCURRENT PROTECTIVE DEVICE PART 1 - GENERAL 1.1 SUMMARY A. Section includes computer-based, fault-current and overcurrent protective device coordination studies. Protective devices shall be set based on results of the protective device coordination study. B. Section includes computer based arc flash hazard analysis study. Recommendations for reducing Arc Flash Incident Energy levels and enhancing worker safety shall be issued based on the results of the study. 1.2 DEFINITIONS A. AFIE - Arc Flash Incident Energy. 1.3 SUBMITTALS A. Product Data: For computer software program to be used for studies. B. Product Certificates: For coordination-study and fault-current-study computer software programs, certifying compliance with IEEE 399, for arc flash study - compliance with IEEE 1584. C. Qualification Data: For coordination-study specialist. Submit names and references for at least five actual Arc-Flash Hazard Analysis performed in the past year. D. Other Action Submittals: The following submittals shall be made after the approval process for system protective devices has been completed. Submittals shall be in digital form. 1. Coordination-study input data, including completed computer program input data sheets. 2. Study and Equipment Evaluation Reports. 3. Coordination-Study Report. 4. Arc Flash Study Report. 1.4 QUALITY ASSURANCE A. Studies shall use computer programs that are distributed nationally and are in wide use. Software algorithms shall comply with requirements of standards and guides specified in this Section. Manual calculations are not acceptable. B. Coordination-Study and Arc Flash Study Specialist Qualifications: An entity experienced in the application of computer software used for studies, having performed successful studies of similar magnitude on electrical distribution systems using similar devices. HERZL CO-LOCATION 260573-1 OVERCURRENT PROTECTIVE DEVICE
1. Professional engineer, licensed in the state of Illinois, shall be responsible for the study. All elements of the study shall be performed under the direct supervision and control of engineer. C. Comply with IEEE 241 and 242 for short-circuit currents and coordination time intervals. D. Comply with IEEE 399 for general study procedures. E. Comply with IEEE 1584-2002 for arc flash calculations procedures. F. Comply with the City of Chicago Electrical Code. 1.5 REFERENCES A. Institute of Electrical and Electronics Engineers, Inc. (IEEE): 1. IEEE 242 Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems. 2. IEEE 241 Recommended Practice for Electric Power Systems in Commercial Buildings. 3. IEEE 1015 Recommended Practice for Applying Low-Voltage Circuit Breakers Used in Industrial and Commercial Power Systems. B. American National Standards Institute (ANSI): 1. C37.13 Standard for Low Voltage AC Power Circuit Breakers Used in Enclosures 2. ANSI Z535.4 Identification of AFIE and appropriate Personal Protective Equipment Classes. PART 2 - PRODUCTS 2.1 COMPUTER SOFTWARE DEVELOPERS A. Computer Software Developers: Subject to compliance with requirements, provide products by one of the following software developers: 1. CGI CYME. 2. EDSA Micro Corporation. 3. ESA Inc. 4. Operation Technology, Inc. 5. SKM Systems Analysis, Inc. 2.2 COMPUTER SOFTWARE PROGRAM REQUIREMENTS A. Analytical features of fault-current-study computer software program shall include "mandatory," "very desirable," and "desirable" features as listed in IEEE 399. B. Computer software program shall be capable of plotting and diagramming time-currentcharacteristic curves as part of its output. Computer software program shall report device settings and ratings of all overcurrent protective devices and shall demonstrate selective coordination by computer-generated, time-current coordination plots. HERZL CO-LOCATION 260573-2 OVERCURRENT PROTECTIVE DEVICE
1. Optional Features: a. Arcing faults. b. Simultaneous faults. PART 3 - EXECUTION 3.1 EXAMINATION A. Examine Project overcurrent protective device submittals for compliance with electrical distribution system coordination requirements and other conditions affecting performance. Devices to be coordinated are indicated on Drawings. 1. Proceed with coordination study only after relevant equipment submittals have been assembled. 2. Proceed with arc flash analysis only after relevant equipment submittals have been assembled. 3. Overcurrent protective devices that have not been submitted and approved prior to coordination study may not be used in study. 3.2 POWER SYSTEM DATA A. Gather and tabulate the following input data to support coordination study: 1. Product Data for overcurrent protective devices specified in other Division 26 Sections and involved in overcurrent protective device coordination studies. Use equipment designation tags that are consistent with electrical distribution system diagrams, overcurrent protective device submittals, input and output data, and recommended device settings. 2. Impedance of utility service entrance. 3. Electrical Distribution System Diagram: In hard-copy and electronic-copy formats, showing the following: a. Circuit-breaker and fuse-current ratings and types. b. Generator kilovolt amperes, size, voltage, and source impedance. c. Cables: Indicate conduit material, sizes of conductors, conductor material, insulation, and length. d. Busway ampacity and impedance. e. Motor horsepower and code letter designation according to NEMA MG 1. 4. Data sheets to supplement electrical distribution system diagram, cross-referenced with tag numbers on diagram, showing the following: a. Special load considerations, including starting inrush currents and frequent starting and stopping. b. Motor full-load current, locked rotor current, service factor, starting time, type of start, and thermal-damage curve. c. Generator thermal-damage curve. d. Ratings, types, and settings of utility company's overcurrent protective devices. HERZL CO-LOCATION 260573-3 OVERCURRENT PROTECTIVE DEVICE
e. Special overcurrent protective device settings or types stipulated by utility company. f. Time-current-characteristic curves of devices indicated to be coordinated. g. Manufacturer, frame size, interrupting rating in amperes rms symmetrical, ampere or current sensor rating, long-time adjustment range, short-time adjustment range, and instantaneous adjustment range for circuit breakers. h. Manufacturer and type, ampere-tap adjustment range, time-delay adjustment range, instantaneous attachment adjustment range, and current transformer ratio for overcurrent relays. i. Panelboards, switchboards, motor-control center ampacity, and interrupting rating in amperes rms symmetrical. 3.3 FAULT-CURRENT STUDY A. Calculate the maximum available short-circuit current in amperes rms symmetrical at circuitbreaker positions of the electrical power distribution system. The calculation shall be for a current immediately after initiation and for a three-phase bolted short circuit at each of the following: 1. Distribution panelboard. 2. Branch circuit panelboard. B. Study electrical distribution system from normal and alternate power sources throughout electrical distribution system for Project. Include studies of system-switching configurations and alternate operations that could result in maximum fault conditions. C. Calculate momentary and interrupting duties on the basis of maximum available fault current. D. Calculations to verify interrupting ratings of overcurrent protective devices shall comply with IEEE 241 and IEEE 242. 1. Low-Voltage Circuit Breakers: IEEE 1015 and IEEE C37.20.1. 2. Low-Voltage Fuses: IEEE C37.46. E. Study Report: 1. Show calculated X/R ratios and equipment interrupting rating (1/2-cycle) fault currents on electrical distribution system diagram. F. Equipment Evaluation Report: 1. For 600-V overcurrent protective devices, ensure that interrupting ratings are equal to or higher than calculated 1/2-cycle symmetrical fault current. 2. For devices and equipment rated for asymmetrical fault current, apply multiplication factors listed in the standards to 1/2-cycle symmetrical fault current. 3. Verify adequacy of phase conductors at maximum three-phase bolted fault currents; verify adequacy of equipment grounding conductors and grounding electrode conductors at maximum ground-fault currents. Ensure that short-circuit withstand ratings are equal to or higher than calculated 1/2-cycle symmetrical fault current. HERZL CO-LOCATION 260573-4 OVERCURRENT PROTECTIVE DEVICE
3.4 A. Perform coordination study using approved computer software program. Prepare a written report using results of fault-current study. Comply with IEEE 399. 1. Calculate the maximum and minimum 1/2-cycle short-circuit currents. 2. Calculate the maximum and minimum ground-fault currents. B. Comply with IEEE 241 and IEEE 242 recommendations for fault currents and time intervals. C. Conductor Protection: Protect cables against damage from fault currents according to ICEA P- 32-382, ICEA P-45-482, and conductor melting curves in IEEE 242. Demonstrate that equipment withstands the maximum short-circuit current for a time equivalent to the tripping time of the primary relay protection or total clearing time of the fuse. To determine temperatures that damage insulation, use curves from cable manufacturers or from listed standards indicating conductor size and short-circuit current. D. Coordination-Study Report: Prepare a written report indicating the following results of coordination study: 1. Tabular Format of Settings Selected for Overcurrent Protective Devices: a. Device tag. b. Circuit-breaker sensor rating; and long-time, short-time, and instantaneous settings. c. Fuse-current rating and type. d. Ground-fault relay-pickup and time-delay settings. 2. Coordination Curves: Prepared to determine settings of overcurrent protective devices to achieve selective coordination. Graphically illustrate that adequate time separation exists between devices installed in series, including power utility company's upstream devices. Prepare separate sets of curves for the switching schemes and for emergency periods where the power source is local generation. Show the following information: a. Device tag. b. Voltage and current ratio for curves. c. No damage, melting, and clearing curves for fuses. d. Cable damage curves. e. Maximum fault-current cutoff point. E. Prepare and include in study completed data sheets for setting of overcurrent protective devices. 3.5 ARC FLASH HAZARD ANAYLSIS A. Perform Arc-Flash Hazard Analysis with the aid of computer software intended for this purpose in order to calculate AFIE levels and flash protection boundary distances. B. Perform Arc-Flash Hazard Analysis in conjunction with a short-circuit analysis and a timecurrent coordination analysis. HERZL CO-LOCATION 260573-5 OVERCURRENT PROTECTIVE DEVICE
C. Submit the results of the Analysis in tabular form, and include device or bus name, bolted fault and arcing fault current levels, flash protection boundary distances, personal-protective equipment classes and AFIE levels. D. Perform the analysis under worst-case Arc-Flash conditions, and describe in the final report when applicable, how these conditions differ from worst-case bolted fault conditions. E. Provide equipment labels in compliance with ANSI Z535.4 to identify AFIE and appropriate Personal Protective Equipment classes. END OF SECTION HERZL CO-LOCATION 260573-6 OVERCURRENT PROTECTIVE DEVICE